/*
 * Copyright (c) 2007, Nubo Technologies
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 *
 *    * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
 *    * Neither the name of the Nubo Technologies nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.nubotech.gwt.oss.client.util;

/**
 *
 * @author jonnakkerud
 * Simple class for Base64 encoding and decoding.
 * Original javascript code was found at http://www.webtoolkit.info/javascript-base64.html .
 */
public class Base64 {
    
    private static final String _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
    
    public static native String decode(String input) /*-{
                var output = "";
                var chr1, chr2, chr3;
                var enc1, enc2, enc3, enc4;
                var i = 0;
                                                      
                input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
                                                      
                while (i < input.length) {
                                                      
                        enc1 = @com.nubotech.gwt.oss.client.util.Base64::_keyStr.indexOf(input.charAt(i++));
                        enc2 = @com.nubotech.gwt.oss.client.util.Base64::_keyStr.indexOf(input.charAt(i++));
                        enc3 = @com.nubotech.gwt.oss.client.util.Base64::_keyStr.indexOf(input.charAt(i++));
                        enc4 = @com.nubotech.gwt.oss.client.util.Base64::_keyStr.indexOf(input.charAt(i++));
                                                      
                        chr1 = (enc1 << 2) | (enc2 >> 4);
                        chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
                        chr3 = ((enc3 & 3) << 6) | enc4;
                                                      
                        output = output + String.fromCharCode(chr1);
                                                      
                        if (enc3 != 64) {
                                output = output + String.fromCharCode(chr2);
                        }
                        if (enc4 != 64) {
                                output = output + String.fromCharCode(chr3);
                        }
                                                      
                }
                                                      
                output = @com.nubotech.gwt.oss.client.util.Base64::_utf8_decode(Ljava/lang/String;)(output);
                                                      
                return output;
        }-*/;
    
    
    // public method for encoding
    public static native String encode(String input) /*-{
                var output = "";
                var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
                var i = 0;
                                                      
                input = @com.nubotech.gwt.oss.client.util.Base64::_utf8_encode(Ljava/lang/String;)(input);
                                                      
                while (i < input.length) {
                        chr1 = input.charCodeAt(i++);
                        chr2 = input.charCodeAt(i++);
                        chr3 = input.charCodeAt(i++);
                                                      
                        enc1 = chr1 >> 2;
                        enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
                        enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
                        enc4 = chr3 & 63;
                                                      
                        if (isNaN(chr2)) {
                                enc3 = enc4 = 64;
                        } else if (isNaN(chr3)) {
                                enc4 = 64;
                        }
                                                      
                        output = output +
                        @com.nubotech.gwt.oss.client.util.Base64::_keyStr.charAt(enc1) + @com.nubotech.gwt.oss.client.util.Base64::_keyStr.charAt(enc2) +
                        @com.nubotech.gwt.oss.client.util.Base64::_keyStr.charAt(enc3) + @com.nubotech.gwt.oss.client.util.Base64::_keyStr.charAt(enc4);
                }
                                                      
                return output;
        }-*/;
    
    private static native String _utf8_encode(String string) /*-{
                string = string.replace(/\r\n/g,"\n");
                var utftext = "";
                                                              
                for (var n = 0; n < string.length; n++) {
                                                              
                        var c = string.charCodeAt(n);
                                                              
                        if (c < 128) {
                                utftext += String.fromCharCode(c);
                        }
                        else if((c > 127) && (c < 2048)) {
                                utftext += String.fromCharCode((c >> 6) | 192);
                                utftext += String.fromCharCode((c & 63) | 128);
                        }
                        else {
                                utftext += String.fromCharCode((c >> 12) | 224);
                                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                                utftext += String.fromCharCode((c & 63) | 128);
                        }
                }
                                                              
                return utftext;
        }-*/;
    
    
    // private method for UTF-8 decoding
    
    private static native String _utf8_decode(String utftext) /*-{
                var string = "";
                var i = 0;
                var c = c1 = c2 = 0;
                                                               
                while ( i < utftext.length ) {
                        c = utftext.charCodeAt(i);
                                                               
                        if (c < 128) {
                                string += String.fromCharCode(c);
                                i++;
                        }
                        else if((c > 191) && (c < 224)) {
                                c2 = utftext.charCodeAt(i+1);
                                string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
                                i += 2;
                        }
                        else {
                                c2 = utftext.charCodeAt(i+1);
                                c3 = utftext.charCodeAt(i+2);
                                string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
                                i += 3;
                        }
                                                               
                }
                                                               
                return string;
        }-*/;
    
}
